The Clam Dissection Taxonomy and General Info Kingdom Animalia –Phylum Mollusca – “soft body” Class Bivalvia – “two valves” Clams are sessile Clams are.

The Clam Dissection

Taxonomy and General Info

• Kingdom Animalia– Phylum Mollusca – “soft body”

• Class Bivalvia – “two valves”

• Clams are sessile

• Clams are filter feeders

External Anatomy

External Anatomy Continued

• two valves: three layers– outer layer: protects against acidic conditions

– middle layer: CaCO3 – strength and structure

– inner layer: iridescent, smooth: protects “soft body” of clam

• creates pearls from grains of sand

Open Sesame

• use scissors to cut connection of posterior and anterior adductor muscles

• pull open with fingers

Internal Anatomy

• Systems:– Muscular– Respiratory– Circulatory– Digestive– Excretory– Reproductive– Nervous

Muscular System

• foot located ventral to the gills

• contracts and expands by filling and releasing hemolyph

• foot used to grab surface and movement

• anterior and posterior adductor muscles:– open and close the valves

Respiratory System

• Gills

• current of water moves over gills where Oxygen is exchanged for Carbon Dioxide

• 2 pair of gills per side

Circulatory System

• Open circulatory sytem

• dorsally located heart – along midline under hinge ligament

• heart pumps hemolymph into hemocoel

• current of water created by siphons moves hemolymph back to heart

Digestive

• mouth >>> esophagus >>> stomach >>> intestine >>> anus >>> excurrent siphon

Excretory System

• kidneys filter hemolymph

• cellular and digestive waste are removed by excurrent siphon

Reproductive System

• separate sexes

• external fertilization

• trochophore larva

Nervous System• three pair of ganglia – connected by nerve

cords– one in stomach– one in foot– one near mouth

• senses:– touch, taste